Is there any way of retaining the dimensions of a bounding box after reflecting an object. E.g. if I create a rectangle and rotate it 45 degrees the bounding box is flush with the rectangle around its perimeter. However if I reflect the rectangle vertically at 90 degrees the bounding box is no longer flush with the rectangle and so I cannot scale the rectangle without losing its original dimensions.

I've tried the reset bounding box option but it doesn't seem to work very well. Is there any way to reflect an object and retain the bounding box perimeter? Thanks.

You need to explain the problem in more detail. I don't see what it sounds like you are trying to describe:

Describe each operation you are performing; every click, tool selection, etc.

In Illustrator,
dimensions of rotated bounding boxes do not reflect the measures of the rotated box. They uselessly reflect the mere vertical and horizontal bounds of the rotated box (like an invisible bounding box of a visible bounding box). Canvas, for example, handles this correctly, giving the user the choice between absolute and relative measures.

Sorry, mistake in my original post. I should have said 30 degrees (or anything other than 45).

Example. Create a rectangle and then rotate it 30 degrees. Create a copy of the rectangle and then reflect it 90 degrees vertically. The image below illustrates the new (post-reflection) bounding box on the left. The rectangle height cannot be changed without losing the width dimensions and vice versa.

The second example below illustrates the problem with a stick man created using a number of rounded rectangles.

The bounding boxes for the reflected stickman (on the left) prevent the limbs from being lengthened correctly.